The trend of soft set-up's is growing in leaps and bounds. People are going to softer set-up because softer spring packages produce grip in the tires.
Just putting in soft springs will not get you the results you need. You will need to know what else to do or expect out of the chassis. So what else do
you do? Here is some of the things you will need to know if you are running a soft spring package in your chassis.
When using soft springs, you need to make sure that the springs do not coil-bind. A spring will start to coil-bind when the spring reaches the last half
inch of the total available spring travel. You can figure out the amount of spring travel you have by setting the chassis at ride height and adding up the
spaces in the coils. Usually there is plenty of spring travel before the chassis will bottom out. If you find that the spring you are using will coil-bind,
you need to get a longer spring so there are more spaces in-between the coils. If you get coil-bind the soft set-up will not work.
Shocks should have more rebound than compression. This will allow the chassis to turn thru the middle of the corner better. You do not need to go drastic,
but a little more rebound will be better. On the two front shocks, the right front shock should have more compression than the left front shock.
The diagonal weight needs to be high. A normal baseline starting point is to be about 2% higher than your left side weight. This will allow you to drive
deep into the corner and get the forward traction you need.
Working with dive and anti-dive will help also. I call this anti-dive split. This is the difference between the left front dive/anti-dive and the right
front anti-dive. Most chassis manufactures' set the upper control arms at about 2 degrees of anti-dive. I like to see about 4 degrees of anti-dive split.
To do this you need to set the left front upper control arm level front to back and the right front control arm at 4 degrees higher on the front side. What
you can expect is, when you enter the corner, the split will allow the left front to dive easier than the right front causing the chassis to stay tight on
entry. When you lift off the brake the chassis will freely travel to the right front allowing that tire to grip and making the chassis turn.
Use a stiff stabilizer bar. On chassis with universal bars, there is a 1 3/8" heavy wall bar that is make for them. This is the bar of choice. This will
help the corner entry by working with the anti-dive and soft springs keeping the chassis from dumping onto the right front corner. In the center of the corner,
the nose will remain flat across (not having much roll) which allows the car to utilize the left front tire more effectively, thus making the car turn good.
The panhard bar and rear springs can be done two different ways to suit the driving style. The panhard bar set low and a stiffer right rear is one way. The
panhard bar set high and a softer right rear is another way. You will need to test this at the track you are running at to see what will work best for you.
A rule of thumb for changing spring and panhard bar height is for every inch of panhard bar height change, 13 lbs of spring rate should be changed. Example:
If you lower the panhard bar 1", you should put a 13 lbs. stronger spring in the right rear.
